The Dunning-Kruger effect is a cognitive bias that causes incompetent people to believe they know more than they think they know.

Unskilled individuals suffer from a false sense of superiority, mistakenly rating their ability much higher than is accurate. This bias is the result of the inability of the unskilled to recognize their own ineptitude.

If you’re incompetent, you can’t know you’re incompetent. The skills you need to produce a right answer are exactly the skills you need to recognize what a right answer is.

—David Dunning

Conversely, highly competent individuals tend to underestimate their relative competence, falsely assuming that tasks which are easy for them are also easy for others.

If this is true (and the research seems to support these conclusions), this explains almost everything.

Ignorant people can’t avoid thinking that they are smart.

Zealots, fanatics, ideologues, judgmental family members, Fox News pundits, preachy douchebags, incompetent politicians, Biblical literalists, New York Jets fans, and the like are trapped in a world where it’s impossible for them realize that they are ignorant because they are ignorant.

This makes their stupidity so much more understandable.

I can see it now:

Some idiot will be spouting off against gay marriage, or trying to explain how vaccines are dangerous, or insisting that backing into a parking spot makes sense. In the past, I might have argued these points. Tried to change the person’s mind. Defended the truth.

No longer will I have to wonder if a person actually believes the nonsense that he or she is spewing. They do. And they can’t help it, because they are incompetent.

The best part of the Dunning-Kruger effect the man who inspired the initial study.

McArthur Wheeler was a man who robbed two banks in 1995 after covering his face with lemon juice in the mistaken belief that, as lemon juice is usable as invisible ink, it would prevent his face from being recorded on surveillance cameras.

David Dunning and Justin Kruger heard about this man and wondered how stupidity of that magnitude is even possible.